A network architecture called “IP Multimedia Subsystem” (IMS) has been developed by the 3rd Generation Partnership Project (3GPP) as an open standard for handling multimedia services and sessions in the packet domain (refer to http://www.3gpp.org/ftp/Specs/html-info/22173.htm). These days, various communication terminals and devices (hereinafter referred to as IMS terminals) are known that conform to an IMS standard. A typical example of an IMS terminal is a mobile phone with IMS functionality. A personal computer (PC), a personal digital assistant (PDA), etc. can also be IMS terminals if they are equipped with IMS functionality. IMS terminals can provide multimedia services by, for example, receiving video streaming from a video-streaming server over an IMS network.
However, there still exist a lot of communication terminals (hereinafter referred to as non-IMS terminals) that do not have IMS functionality. International Publication No. WO 2006/045706 discloses a multimedia gateway called a “Home IMS Gateway” (HIGA), which enables these non-IMS terminals to access the IMS network.
According to WO 2006/045706, the HIGA is located in a private network, to which at least one non-IMS terminal is connected. The HIGA includes a Session Initiation Protocol (SIP) Back-to-Back User Agent (B2BUA) for communications between non-IMS terminals and the IMS network. The HIGA also includes a SIP gateway (implemented according to 3GPP TS 24.229 and IETF RFC 3261). The SIP gateway allows inter-working between various client terminal signalling protocols and the SIP used by the IMS. For example, the SIP gateway may provide translation between ISDN-based signalling protocols and SIP. Accordingly, the non-IMS terminals may or may not have SIP functionality.
The B2BUA is equipped with an IMS Subscriber Identity Module (ISIM) application that stores an IMS Private Identity (IMPI) for respective non-IMS terminals as well as at least one IMS Public Identity (IMPU) for respective non-IMS terminals. The B2BUA handles IMS signalling on behalf of non-IMS terminals such that all signalling concerning respective non-IMS terminals is associated with the corresponding IMPI on the ISIM application. For example, if a non-IMS terminal sends an SIP REGISTER message to the HIGA, the B2BUA translates the message into an IMS REGISTER message that contains both an IMPI and an IMPU corresponding to the non-IMS terminal. Thus, the HIGA act as an IMS terminal on behalf of the non-IMS terminal, thereby enabling the non-IMS terminal to access the IMS network.
Non-IMS terminals (as well as IMS terminals) in the private network can communicate with the HIGA using an architecture according to Universal Plug-and-Play (UPnP). UPnP is developed in a multi-vendor collaboration for establishing standard device control protocols. UPnP provides peer-to-peer connectivity for communication between all types of devices in the private network, regardless of access technology, operating system, programming language, format standard, and communication protocol of the device. The UPnP technology is based on Internet standards such as IP, TCP, UDP, HTTP, and XML, and can use any transport medium such as a telephone line, Ethernet and different types of wireless media. UPnP defines base protocol sets for each type of device.
Further, UPnP supports an automatic “discovery” process, also referred to as “pairing”. Using the discovery process, a local device can dynamically join a private network, obtain a private IP address, announce its name and IP address, and provide its capabilities to other devices (i.e., terminals in the private network) upon request. In this way, each local device in the private network can also obtain information on the presence and capabilities of other devices in the private network.
Digital Living Network Alliance (DLNA) is a new technology developed by leading manufacturers of electronic consumer equipment for acquiring, storing and accessing digital content such as music, films and images from any device in a private network. Devices with DLNA functionality (hereinafter referred to as DLNA devices) incorporate a networking component called “Device and Service Discovery and Control” for automatic self-configuration of networking properties such as private IP addresses, which corresponds to the above-mentioned discovery functionality of UPnP. To accomplish this functionality, DLNA uses a standardized UPnP protocol according to the UPnP Device Architecture, Version 1, providing simple and effective device networking in the home.
Nowadays, it is desired to make it possible for a remote device located outside the private network to access local devices in the same manner as when located inside the private network. A co-pending International Patent Application No. PCT/SE2006/004122, filed on Sep. 13, 2006, addresses this desire.
According to PCT/SE2006/004122, the HIGA is configured to enable the remote device to access the local devices in the private network. In addition, the HIGA has pre-stored authentication information indicating which users or remote devices are permitted to access local devices in the private network. Thus, the HIGA authenticates the remote device and prevents an unauthorized remote device from invading the private network.
However, PCT/SE2006/004122 does not address how to pre-store the authentication information in the HIGA. One possible solution could be that the user manually registers the authentication information in the HIGA, but this solution will be burdensome for the user.
The present invention has been conceived in light of the above-mentioned problem, and it is a feature thereof to reduce the user's burden to register authentication information in an HIGA, as well as to enable the remote device to access local devices by means of the HIGA.